Valve gear for steam engines



(No Model) v 2 Sheets-Sheet 1.

L. 0. BURK. VALVE GEAR FOR STEAM ENGINES.

No. 531,096. Patented Dec. 18,1894.

INVENTOH Let Mm.

ATTORNEYS (No Model.) 2 Shees+Sheet 2.

L. 0. BURK. VALVE GEAR FOR STEAM ENGINES.

No. 531,096. Patented Dec. 18,1894.

HIEHHIIIIIIIIIH WITNESSES:

' yljm Elvrofi ATTORNEYS.

. .Urvrrs STATES ATENT Er c.

LEMON o. BURK, or .OORN'ING, ARKANSAS, ASSIGNOR TO HIMZSEILF AND DOUGLASHOPSON, or SAME PLACE.

VALV E-GEAR- FOR STEAM-ENGINES.

SPEGIFIGl LTION forming part of Letters Patent No. 531,096, datedDecember 18, 1894.

Application filed June 1,1894. Serial N0. 513,153- (No model.)

To all whom it may concern:

Be it known that I, LEMON O. BURK, of Corning, in the county of Clay andState of Arkansas, have invented a new and Improved 5 Valve-Gear forSteam-Engines, of which the following is a full, clear, and exactdescription. The object of the invention is to provide a new andimproved valve gear, which is simple and durable in construction, veryeffective in operatiomand arranged to permit of conveniently reversingtheengine and delivering the steam directly into the ends of thecylinder.

The invention consists in certain parts and be hereinafter fullydescribed and then pointed out in the claims.

Reference is to be had to the accompanying drawings, forming part ofthis specification, in which similar letters of reference indicatecorresponding parts in all the views.

Figure 1 is a plan view of the improvement. Fig. 2 is a side elevationof the same. Fig. 3 is a sectional side elevation of the same, on theline 3-3 of Fig. 1. Fig. etisa transverse section of the same, on theline 44. of Fig. 3.

Fig.5 is a similar view of the same, on the ends of the cylinder A arearranged the straight ports a and 1), opening directly into the steamchest F, containing two valves G} and G, operating over the said ports aand b respectively, to control the inlet of the live steam to the said03 linder and the outlet of exhaust steam therefrom. The two valves Gand G are connected with each other by a valve stem G and the saidvalves are preferably made semi-circular in cross section, and arefitted to slide in correspondingly- 5o shaped casings H and H, fitted inthe ends of the steam chest F, and open at their ends,

compartment of the steam chest.

details, and combinations of the same, as will H and H can be removedand are held in position by suitable lugs H projecting from the insideof the steam chest, as plainly indicated in Fig. 6. The valves G and Gdivide the steam chest into three compartments, of which the centralcompartment is connected with the inlet steam pipe F, leading to theboiler or other steam generator, so as to permitlive steam to enter andfill the middle The end compartments of the steam chest are connectedwith exhaust pipes F and F leading to the outside.

The outer end G of the valve stem G2 is pivotally connected by aconnecting rod I with a block J, fitted to slide in the verticallydisposed slot K of the link K, having trunnions K and K journaled insuitable bearings on the main frameof the engine. The

outer end of the trunnion K carries a crank arm K formed in its lowerend with a slot K engaged by anadju'stable wrist pin L, connected withthe eccentric rod N of an eccentric N held on the main driving'shaft E.

nions, so that the block J held ineither'the upper or lower end of thesaid link, is carried forward and backward 0n the rocking of the link.This motion of the block J is transmitted by the connecting rod I, tothe valve stem G so that a reciprocating motion is given to the valves Gand G in the steam chest F, to regulate the inlet of live steam to theends of the cylinder, and'the outlet of exhaust steam from the cylinderin the usual manner. Now, in order to change the position of the block Jin the slotted link K, to reverse the engine, I provide the followingdevice: The connecting rod I, is connected near its front end with aneye 0 held on an arm 0 secured on a transversely-extending shaft P,journaled in suitable bearings arranged on the main frame of the engine.On the outer end of this shaft P is secured a downwardly-extending arm Qconnected by a link Q with a reversing lever B, carrying the usuallocking pawl R, adapted to lock the reversing lever on the segment S onwhich the reversing lever is pivoted. See Fig. 2. Now, when the severalparts are in the position illustrated in Fig. 2, and the operatordesires to reverse the engine, then he first unlocks the pawl R and thenmoves the reversing lever B to the right so as to shift the link Q toimpart a swinging motion to the shaft P by the arm Q. The rocking of theshaft P causes an upward swinging of the armO, whereby the eye 0 impartsan upward swinging to the front end of the connecting rod I, whereby theblock J is transferred from its lowermost position in the link K to theuppermost end, that is, on the opposite side of the trunnions K and K Assoon as the block J slides past its central position in the link K, thevalves G and G will be reversed, which reverses the engine in the usualmanner.

By shifting the reversing lever B to an intermediate position the blockJ maybe moved nearer to the trunnions from either end, so as to cut offsooner or later as desired. Each of the valves G and G is provided witha suitable packing pressed by springs into contact with the segmentalwall of the respective casing 11 or H, so as to prevent steam fromleaking from the central compartment to the end compartments of thechest. The valve stem G is threaded and the valves G and G are.

held on the said rod by nuts screwing on the threaded portions of thevalve stem, and on opposite sides or faces of the valves, as plainlyindicated in Fig. 3.

The link K is made segmental, as plainly illustrated in Figs. 2 and 3,the center of the segment being in the center of the connection betweenthe end G3 of the valve stem and the connecting rod 1.

By the arrangement described the ports a and b are veryshort anddirectly connect the cylinder with the steam chest so that the livesteam can pass directly into the ends of the cylinder and thus insurefull boiler pressure in the cylinder to act on the piston B. It willfurther be seen that the valves G and G balance each other, as the steampressure is alike on both inner faces of the said valves.

Having thus described my invention, 1 claim as new and desire to securebyLetters Patent- 1. A device of the class described, comprising areversing link adapted to be rocked from the main shaft, a block fittedto slide in the said reversing link, a connecting rod for connectingtheblock with the valve stem, and a raising and lowering device for thesaid connecting rod, to move the block in the said reversing link, saiddevice comprising a rock shaft having a rigidly connected arm providedwith an eye through which the connecting rod slides, and means foradjusting the rock shaft substantially as shown and de scribed.

2. A valve gear for steam engines, comprising the slotted rocking linkhaving a crank arm linked to the main shaft, a block adjustable in theslotted link, a cross head connected to the slide valve in the steamchest, a rod connecting said cross head with the block, a crank shaftabove the cross head and having a rigidly connected arm projectingtoward the slotted link and provided with an eye through which theconnecting link reciprocates and an operating lever connected to thesaid rock shaft and provided with a locking mechanism, substantially asdescribed.

3. The combination with a steam chest provided at its ends with openingsand removable cover sections, valve casings in the ends of the casingand removable upwardly through said end openings, the middle portion ofthe chest forming the chamber for live steam and the portions beyond thesaid casings forming the exhaust chambers, ports a 1) leading directlyfrom the two valve casings into the cylinder and two connected slidevalves working in said casings, substantially as described.

4. The combination with the steam chest having openingsin its top atboth ends, cover sections therefor, lugs 11 in the side walls of thechest in line with the openings, valve casings inserted removably intothe chest through said openings and held in place by said lugs, portsa 1) leading from the live steam chamber into the cylinder and exhaustchambers in the ends of the chest, of the two connected valves mountedin the respective valve casings and provided with spring seatedpackings, substantially as described.

LEMON O. BURK.

Witnesses:

H. J. WEINAD, L. S. FERGUSON.

